Message267616
Martin Panter (msg267504): "As I understand it, if there is no entropy initialized, this patch will fall back to reading /dev/urandom, which will return predictable data (opposite of “random” data!)."
No, I don't think so.
Linux uses a lot of random sources, but some of them are seen as untrusted as so are added with a very low estimation of their entropy. Linux even adds some random values with a estimation of 0 bit of entropy. For example, drivers can add serial numbers as random numbers.
So even if getrandom() blocks, if the urandom entropy pool is not considered as fully initialized yet, I expect that /dev/urandom still generates *random* numbers, even if these numbers are not suitable to generate cryptographic keys.
Please double check, I'm not sure of what I wrote :-)
See also http://www.2uo.de/myths-about-urandom/ (but this article doesn't describe how urandom is initialized). |
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Date |
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2016-06-07 10:14:36 | vstinner | set | recipients:
+ vstinner, lemburg, rhettinger, doko, larry, matejcik, ned.deily, skrah, python-dev, martin.panter, ztane, thomas-petazzoni, Colm Buckley |
2016-06-07 10:14:36 | vstinner | set | messageid: <1465294476.28.0.138546142865.issue26839@psf.upfronthosting.co.za> |
2016-06-07 10:14:36 | vstinner | link | issue26839 messages |
2016-06-07 10:14:35 | vstinner | create | |
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